近年来 ,高碑店市夏玉米每年都发生不同程度的黄苗现象 ,初期玉米幼苗叶片发黄 ,下部叶片叶尖和叶缘干枯 ,并逐渐扩展至整个叶片干枯 ,严重时呈枯焦灼烧状 ,植株生长发育缓慢 ,甚至死亡 ,有的地块是点片发生 ,有的是整块地全部发生 ,从而造成严重经济损失 ,但户与户之间的差异 In recent years, the summer maize in Gaobeidian City undergoes different degrees of yellowing phenomenon every year. The leaves of early maize seedlings are yellow, the leaf tips and leaf margins of the lower leaves are dry, and gradually expand to dryness of the whole leaves, , Plant growth and development of slow, or even death, and some plots are spots, and some are all occurred in one piece, resulting in serious economic losses, but the difference between households